1. Field of the Invention
The present invention relates to a seal element, in particular an elastomer gasket for use in hydraulic annular cylinders, for example in slave cylinders of motor vehicles, such as in clutches, which seal element has a radially outer and a radially inner seal lip.
2. Background Information
A similar known seal element or sealing structure is disclosed in German Patent No. 41 09 125 A1, for example. This known structure describes a concentric slave cylinder for the hydraulic actuation of the clutch of a motor vehicle, which slave cylinder is realized in the form of an annular cylinder. The annular cylinder by means of which cylinder the release bearing is actuated, must be sealed radially externally with respect to the housing of the slave cylinder, and radially internally against the cylinder jacket which cylinder jacket surrounds the transmission drive shaft. An outer and an inner seal lip are provided for this purpose.
To make available a sufficient actuation travel, it must be possible for the annular piston to travel an appropriate distance. In order to insure that the result is a sufficient guide length for the annular piston, the slave cylinder must be realized so that it is sufficiently long.
The increasing optimization of the utilization of space in motor vehicles, which goes hand in hand with the increase in the number of models and the variety of optional equipment available, basically requires that all of the components be designed in a compact and space-saving manner. Consequently, a slave cylinder must have a minimal inserted length if this requirement is to be met. These two requirements are in direct competition with one another. In addition, while in the inserted position, the gasket of the annular piston must not impact axially against housing parts, so that no damage to the individual parts occurs.
A reduction of the length of the seal element described above would reduce the structural length of the slave cylinder to the same extent when the annular piston is inserted. For reasons of stability, there are inherent or natural limits on the possible reduction of the height of the gasket.
In other words, any reduction in the size of the annular piston-sealing element combination would reduce the size of the slave cylinder by the same extent. The slave cylinder need only be of sufficient length to receive the annular piston and sealing structure without having the sealing structure impact against the housing parts. Therefore, any reduction in sealing element size may result in a reduction in the slave cylinder size.